PLCs are important and necessary elements when working with automated industrial processes. A major driving force in industry and thus the economy as a whole rests with industrial output. The front line of industry can then be regarded as the factories, where automated systems help mass-produce numerous products on assembly lines and other like systems. In order to accomplish industrial goals, it is crucial that the automation is controlled properly. Making this even more important is the fact that factories often feature dusty and extreme temperature conditions that can interfere with computers and other systems.
At the heart of this automation is the PLC. The general PLC is designed to withstand such conditions inside the factory in order to create a more effective automated environment. The PLCs function is to utilize hardware and software capabilities to basically control the automated process. A central processing unit (CPU) generally interfaces with an input/output system (I/O module) to ultimately engage the controlling process through the additional use of sensors, switches and other devices. The output of this interaction within the PLC is crucial as timing, voltage, current and other factors must be at specification to properly control the automation process. Basically, if an output result is not responded to in a certain amount of time, the control will be off and thus will cause the entire overall automation process to be off and not in proper control.
In addition, analog I/O modules are vitally important to industry as these elements of the PLCs are relied upon to measure dimensions and other such significant elements as motion, pressure and temperature. In this regard, there is a significant need for a monitoring system that can directly and easily monitor the units of voltage and other factors. In its most basic sense, this type of monitoring is used to ensure that everything is working properly.
Currently, most designs require meters or additional computer connections to determine whether the controller and consequently the entire automation is running properly. These meters and additional computers employ a process where the PLC output gleaned from the sensors and I/O modules read the output for an item such as voltage. However, the meter and additional computer approaches require costly and invasive methods that delay the overall monitoring process. In addition, the meter and additional computer approach often require that parts be taken out of the overall component and transferred to the external monitoring device. This creates more issues as it can affect the quality of this vital reading. For example, a meter used to decipher digital output can actually cause a reading to change when placed near the circuits. Even a slight change in the reading can cause costly problems for the overall automation. It should be noted that removing covers and moving cables could affect monitoring. Current display methods involve this type of invasive activity, which perpetuates inherent issues of skewed data. Because of these factors, there is a substantial need for a display and monitoring method that is non-invasive. By satisfying this need of a non-invasive monitoring method such as is the case with the present invention, controllers and industrial automation in general will greatly benefit from this added safeguard related to the fact that a user can simply read the data without adversely affecting with vital elements of the control system.
Recognizing the importance of constant monitoring, some have incorporated attempts at providing better monitoring devices to the analog I/O modules. For example, light-emitting diodes (LED) have been attached that illuminate as an alarm system when something such as voltage output is outside a desired range. However, this alarm system merely issues an alert and does not eliminate the typical requirement to intervene with the functionality of the PLC in order to establish a meter or additional computer for an output reading.
Currently, there is no way for a person in real-time to physically view an analog I/O module and determine exactly what is being sent to the CPU of the PLC. Thus, there is a need for a device that contains a LCD-type element that actively displays what has been converted and sent to the CPU in real-time. This need is substantial because a device such as the present invention will allow a person to see the exact condition of the analog I/O module at any given time. This then will eliminate all the extraneous steps that are currently undertaken. This need is established with the present invention because a user can use the present invention to view the digital data in counts, as well as in engineering units. By satisfying this need, automated industry will significantly benefit through the much more cost-effective and increased monitoring of the analog I/O module output.
U.S. Pat. No. 5,640,099 issued to Sanada on Jun. 17, 1997, is a method and apparatus for detecting a short circuit point between wiring points of a device. Unlike the present invention, Sanada employs costly elements such as laser beams to merely detect deficiencies and does not convert conditions such as voltage and temperature into digital data.
U.S. Pat. No. 5,058,052, issued to Sexton et al on Oct. 15, 1991, is a method for checking for errors in a PLC based on a predetermined list of possible deficiencies to be concerned about. When a deficiency is discovered, an error alert commences to inform a user that there may be a problem with the control. Unlike the present invention, Sexton is a relatively costly endeavor in that it integrates merely an alert mechanism to inform a user of a deficiency. The user must then take additional and invasive steps to determine the exact issue with the PLC instead of having the opportunity to quickly read a real-time display to determine the exact deficiency, as is the case with the present invention.
There is a distinct need to quickly and accurately detect output deficiencies in PLCs due to the strict timing and often rough conditions associated with the control of automated industrial elements. While alert methods certainly have the ability to let a user know of a problem, the fact remains that the problem either has already occurred or time must be taken to determine what exactly the problem is. A related issue to these alert methods is that they become costly in both additional material and time as an investigation of the potential deficiency is investigated. Thus, there is a need for a non-invasive device that can always be available to convert and send voltage or current signal into digital data counts or engineering units to the CPU and display them in real-time.
The present invention satisfies that need and is significant in that it provides a cost-effective and practical method for quickly monitoring the progress of the controller output relating to an analog I/O module. At the same time, the present invention also is unique in the fact that it allows a user to monitor data without having to potentially compromise the results—even just a tiny bit—because of the non-invasive method of display.
Moreover, the present invention allows for the proper verification of a system at any time and in real-time without the invasive need for fiddling with internal parts or cables. At the same time, most other PLC displays rely on intermediate elements throughout the system to complement the function relating to the invasive methods of monitoring. Beyond the typical invasive problems, these intermediate systems sometimes interfere with the regular flow and process of the data. This problem sometimes leads to the corruption of data. The present invention, however, solves this problem by directly connecting the I/O card to the display interface. This essentially cuts out the negative effects of these intermediate elements while also sparing the monitoring system of potentially data-skewing invasive procedures. For these reasons, there is a substantial need for the present invention.